Relcocation of application-specific functionality during seamless network layer-level handoffs

ABSTRACT

The present invention provides a relocation of an application-specific functionality for an application that a mobile terminal (mobile node) is executing. Entities that may provide application-specific functionalities that assist the application include a location-based server (that may be associated with a supplementary service provider functionality), a transcoder proxy, and a security gateway. The relocation of the application-specific functionality with a network layer-level handoff enables the mobile terminal to seamlessly execute an application that utilizes the media content from a content source that is supporting the mobile terminal before the handoff Subsequent to the handoff, the mobile terminal registers with a current access router in order to inform the current access router about application context information. In the exemplary embodiments, the access routers and the content source support the discovery of an entity that can support the application-specific functionality and the configuration of the application-specific functionality after the handoff.

FIELD OF THE INVENTION

[0001] The present invention relates to the relocation of anapplication-specific functionality, such as a supplementary serviceprovider functionality, for a mobile terminal during a networklayer-level handoff.

BACKGROUND OF THE INVENTION

[0002] Providing seamless services is a critical issue for mobilenetworks. In the context of services supported by the Internet protocol(IP), seamless IP-layer connectivity is necessary as a mobile terminalhandoffs to a new access router with minimal disruption to the mobileterminal's Internet connectivity. There are several approaches toproviding IP connectivity. First, the mobile IP protocol describes amechanism that allows packets to be routed through the Internet to a newaccess router when the mobile terminal changes its point of attachmentto the Internet from an old access router to the new access router.Also, after having established link-layer connectivity with the newaccess router, the mobile terminal engages in signaling the new accessrouter in order to obtain its new care-of-address. When obtaining thenew care-of-address, the mobile terminal has acquired IP-levelconnectivity with the new access router so that the mobile terminal cantransmit and receive packets with the new access router. A fast handoffprotocol enables forming the new care-of-address while the mobileterminal is still attached to the old access router. As soon as themobile terminal acquires link-layer connectivity with the new accessrouter, the mobile terminal can transmit and receive packets with thenew access router.

[0003] Moving the mobile terminal's point of attachment to the Internetfrom the current access router to the new access router may not sufficeto provide seamless service if the mobile terminal's applicationrequires additional features for packet transport such as transportquality of service (QoS), security, and header compression. Thesefeatures need to be provided at the new point of mobile terminal'sattachment to the Internet after IP-layer handoff. This can be achievedvia context transfer framework. Current approaches to a context transferframework limit solutions to seamless IP-layer connectivity and do notaddress the service and business related aspects. In other words,ability to exchange packets with the Internet in an uninterruptedfashion in the light of handoffs as considered by current approaches,does not necessarily mean that the multimedia application on the mobileterminal will continue seamlessly. This is because, applications maymake use of certain application-specific network functionalities, whichmay need to be relocated or provisioned concurrently with IP-layerhandoffs.

[0004] For example, a mobile terminal (mobile node) may be accessing anInternet application that is provided by a content source such as linenavigation, which depends upon the mobile terminal's geographicallocation. Typically, the content source uses a supplementary serviceprovider functionality that is specific to the network serving themobile terminal. In the case of a location service, for example,selecting the supplementary service provider functionality according tothe serving network may be necessitated by the dependence of radioaccess technology that the mobile terminal is utilizing (globalpositioning satellites, time difference of arrival, angle difference ofarrival, RF badges, and so forth) as well as by the physical wirelessenvironment (e.g. indoor or outdoor). Moreover, the supplementaryservice provider functionality is accessing highly confidential data,namely the mobile terminal's location, and hence the supplementaryservice provider functionality has a special trust relationship with theadministrative entity of the network domain that is serving the mobileterminal.

[0005] If the mobile terminal handoffs to another administrative domain,either by migrating to another network operator that uses the same radiotechnology as the previous network operator or by switching to anotherradio access technology of another network operator, the currentsupplementary service provider functionality may not be able to providemobile terminal's location information to customize the content from thecontent source to the mobile terminal. Even though the mobile terminalmay experience seamless IP-network connectivity, an application that themobile terminal is utilizing before the handoff may not be able tocontinue after the IP-level handoff because the content source does nothave access to an appropriate supplementary service providerfunctionality. Hence, with the increasing importance of supportingenhanced services to a mobile terminal over the Internet, there is aneed to support application-specific functionality in a seamless manner.

SUMMARY OF THE INVENTION

[0006] The aspects of the present invention provide a relocation of anapplication-specific functionality for an application that a mobile nodesuch as a mobile terminal is executing. Entities that may provideapplication-specific functionalities that assist the application includea location tracking server (that may be associated with a supplementaryservice provider functionality), a transcoder proxy, and a securitygateway. The relocation of the application-specific functionality with anetwork layer-level handoff (e.g. an IP-level handoff) enables themobile terminal to seamlessly execute an application that utilizes themedia content from a content source that is supporting the mobileterminal before the handoff Prior to the handoff, the mobile terminalregisters with a current access router in order to inform the currentaccess router about application context information.

[0007] In a first exemplary embodiment of the invention, preceding thehandoff, the current access router informs a new access router aboutapplication context information that is indicative of the requiredapplication-specific functionality. Subsequently, the new access routerdiscovers an entity that can support the application-specificfunctionality in the associated wireless network. The new access routeralso configures the application-specific functionality and informs thecontent source to continue the packet data stream to a new care-ofaddress after the handoff and to utilize the configuredapplication-specific functionality. It may also inform the mobileterminal about the address and characteristics of the configuredapplication-specific functionality.

[0008] In another exemplary embodiment of the invention, the contentsource discovers the entity that can support the applicationfunctionality in the associated wireless network. Also, the contentsource configures the application-specific functionality. The contentsource may continue transmitting the packet data stream to the mobileterminal utilizing a new care-of address that is provided by the newaccess router.

[0009] In another exemplary embodiment of the invention, the new accessrouter discovers the entity that can support the applicationfunctionality in the associated wireless network. The content source isprovided information about the discovered entity, and the content sourcesubsequently performs its part of configuration of theapplication-specific functionality. The content source may continuetransmitting the packet data stream to the mobile terminal utilizing anew care-of address that is provided by the new access router. Themobile terminal may also be informed about the discovered entity, andthe mobile terminal subsequently performs its part of configuration ofthe application-specific functionality.

BRIEF DESCRIPTION OF THE DRAWINGS

[0010]FIG. 1 shows a first architecture supporting anapplication-specific functionality, such as a supplementary serviceprovider functionality according to some embodiments of the invention;

[0011]FIG. 2 shows a second architecture supporting anapplication-specific functionality according to some exemplaryembodiments of the invention;

[0012]FIG. 3 shows a messaging scenario in which an access routerdiscovers and configures an application-specific functionality accordingto an embodiment of the invention;

[0013]FIG. 4 shows a messaging scenario in which a content sourcediscovers and configures an application-specific functionality accordingto an embodiment of the invention;

[0014]FIG. 5 shows a messaging scenario in which a hybrid approach isutilized to discover and to establish an application-specificfunctionality according to an embodiment of the invention; and

[0015]FIG. 6 shows apparatus for a mobile terminal, an access router,and a content source in accordance with an embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

[0016]FIG. 1 shows an architecture 100 that supports anapplication-specific functionality, such as a supplementary serviceprovider (SSP) functionality, in accordance with some embodiments of theinvention (as will be discussed in the context of FIGS. 3, 4, and 5). InFIG. 1, a mobile node such as a mobile terminal 101 a receives packetsfrom a content source 103 through a path 161, a border router (BR) 105,a path 163, a gateway router (GR) 107, a path 165, an access router (AR)109, and a wireless communications channel 151. In the embodiments,paths 161, 163, and 165 may utilize an Internet protocol (IP). Thepackets may support different types of content including audio, video,and multimedia formats. In the exemplary embodiments, the packets aretransported through the Internet 130 that utilizes IP, although otherembodiments may support other network layer protocols.

[0017] Mobile terminal 101 a is served by a wireless network 120, whichis connected to Internet 130 through gateway router 107. Access router109 typically communicates to mobile terminal 101 a through a basetransceiver station (BTS) that may support different wirelesstechnologies such as code division multiple access (CDMA), global systemfor mobile communications (GSM), and IEEE 802.11 (Wireless Local AreaNetworks Standards).

[0018] In the exemplary embodiments, a service that is provided tomobile terminal 101 a may comprise the content generated by contentsource 103 in concert with a supplementary service functionality that isprovided by a supplementary service provider (SSP) 115. Supplementaryservice provider 115 serves a mobile terminal 101 a when the mobileterminal 101 a is located within network 120.

[0019] The content from content source 103 may be dynamically modifiedaccording to information about mobile terminal 101 a as determined bysupplementary service provider 115. With the exemplary embodiments shownin FIGS. 3, 4, and 5, for example, content source 103 may use locationinformation about mobile terminal 101 a for location-dependent contentin which mobile terminal 101 a is provided driving instructions to adesignated location. Location-based information may also be used toprovide targeted advertisements to mobile terminal 101 a. Content source103 communicates with supplementary service provider 115 through a path171, border router 105, a path 173, gateway router 107, and a path 175.

[0020] A supplementary service provider (e.g. SSP 115) is typicallyspecific to a network (e.g. network 120) in which mobile terminal 101 ais currently attached. With some embodiments, the utilized technologyfor the provision of the supplementary service functionality may bedifferent for different networks (e.g. network 120 and network 140).With a location tracking supplementary service functionality,supplementary service provider 115 and supplementary service provider117 may utilize time/angle difference of arrival, global positioningsatellites (GPS), coarse tracking based on cell number, or indoortracking using RF badges, depending upon the underlying radio technologyand the physical environment of the associated network. (For example,network 120 may support analog service while network 140 supports thirdgeneration digital service. Or, network 120 may be outdoor cellularnetwork while network 140 could be indoor wireless LAN.) The differenceof radio technologies and physical environments may necessitate thatsupplementary service providers 115 and 117 utilize different locationalgorithms.) Also, a network administrator of network 120 or 140 may notbe able to utilize an associated supplementary service providerfunctionality when mobile terminal 101 a is not located in theadministrator's network domain.

[0021] Mobile terminal 101 a may change its location within network 120(as characterized by mobility) and may be subsequently served by anetwork 140 if mobile terminal 101 a migrates into network 140. Network140 may serve a different geographical area and may utilize a differentwireless technology than network 120. If mobile terminal 101 a movesinto network 140 (as shown as a mobile terminal 101 b), continuedservice needs to utilize a different supplementary service provider,thus necessitating a change from supplementary service provider 115 tosupplementary service provider 117. The some embodiments of theinvention (corresponding to FIGS. 3, 4, and 5) reconfigure the serviceso that supplementary service provider 117 provides the supplementaryservice functionality after the completion of an IP-level handoff 102.After handoff 102, mobile terminal 101 b receives packets from contentsource 103 through path 161, border router 105, a path 167, a gatewayrouter 111, a path 169, an access router 113, and a wirelesscommunications link 153. Content source 103 communicates withsupplementary service provider 117 through path 171, border router 105,a path 177, gateway router 111, and a path 179.

[0022]FIG. 2 shows an architecture 200 supporting anapplication-specific entity (ASE) 215 or 217 according to exemplaryembodiments of the invention that are shown in FIGS. 3, 4, and 5.Application-specific entity 215 and 217 provide an application-specificfunctionality. An application-specific functionality may supportfundamental functionality such as security functionality and transcodingfunctionality. With architecture 200, application-specific entity 215intervenes between communicating endpoints (e.g. mobile terminal 101 aand content source 103). Application-specific entities may support apacket data stream from content source 103 (e.g. a transcoder) orpackets from mobile terminal 101 a and content source 103 (e.g. asecurity gateway). Content source 103 communicates to 101 a through apath 271, border router 105, a path 273, gateway router 107, a path 275,application-specific entity 215, a path 277, access router 109, andwireless communications channel 151.

[0023] With architecture 200, application-specific entity 215 may be atranscoding function that supports format conversion, data sizereduction, and customizing multimedia web content such as images andvideo. The transcoding function enables transmission betweencommunication endpoints (e.g. mobile terminal 101 a and content source103) to be delivered over low bandwidth and error-prone wireless linksand to be processed according to capabilities of mobile terminal 101 a.If, for example, mobile terminal 101 a initiates a streaming videoapplication from a third generation (3G) cellular coverage area(corresponding to network 120) and handoffs into a second generation(2G) cellular coverage area (e.g. network 140), an appropriatetranscoding function (e.g. application-specific entity 217) may need tobe configured in order to match the bandwidth constraints of network140. Moreover, application-specific entity (such as a transcodingentity) 215 may not be accessible because packets may be directlytransmitted from content source 103 and network 140. After handoff 102,content source 103 communicates with mobile 101 b (as designated afterhandoff 102) through path 271, border router 105, a path 279,application-specific entity 217, a path 281, gateway router 111, a path283, access router 113, and wireless communications link 153.

[0024] Application-specific entity 215 may also support a securityfunction. Security associations may be at an application level or at anetwork level (e.g. IP). With an IP-level security association, 215 mayutilize IPsec, in which a security association can be established usingeither an Internet Key Exchange (IKE) protocol or a manual configurationprocedure. IPsec tunneling encapsulates the original packet inside a newpacket.

[0025] An IPsec security association may be established between securitygateways (as may be supported by application-specific entity 215 andapplication-specific entity 217) and communication endpoints (such ascontent source 103). In such a case, mobile terminal 101 a relies on asecurity gateway (application-specific entity 215) when attached toaccess router 109 (serving network 120). Packets from mobile terminal101 a traverse between application-specific entity 215 and contentsource 103 in a secure manner. When mobile terminal 101 a (designated as101 b after handoff 102) handoffs from network 120 to network 140, a newIPsec security association is established between application-specificentity 217 and content source 103.

[0026]FIG. 3 shows a messaging scenario in which access router 113discovers and configures an application-specific functionality accordingto a first exemplary embodiment of the invention. With a transactionsprocedure 301, mobile terminal 101 a and content source 103 set up adata session in order to initiate the packet data stream from currentcontent source 103 to mobile terminal 101 a through current accessrouter 109. Typically, current access router 109 is unaware of specificcharacteristics of end-user applications being executed by mobileterminal 101 a. In the embodiment, hyper text transfer protocol (inaccordance with Internet Engineering Task Force RFC 2616) is utilized,although other embodiments may utilize session initiation protocol (SIPin accordance with Internet Engineering Task Force RFC 2543) or otherprotocols. The content of the HTTP or SIP messages that are exchangedbetween mobile terminal 101 a and content source 103 are typically notvisible to current access router 109 during transaction 301.Consequently, a registration procedure 303 is executed by mobileterminal 101 a in order to explicitly register application contextinformation with current access router 109. The application contextinformation indicates the required application-specific functionality.In the embodiment, registration procedure 303 utilizes Internet controlmessage protocol (ICMP that is specified in Internet Engineering TaskForce RFC 792), user datagram protocol (UDP), transmission controlprotocol (TCP), or any standard method of message transfer between nodesin an IP network. Other embodiments may utilize other protocols such ashypertext transfer protocol.

[0027] The format of the application context information is dependentupon the specific application. In the embodiment, the applicationcontext information comprises an content profile and a mediadescription. Some exemplary applications include location serviceapplications, transcoder service applications, and security gatewayapplications. With a location service application, the applicationcontext information may describe a need for a location server and acontent source (e.g. content source 103) that is authorized to receivelocation information. With a transcoder service application, theapplication context information may describe a media coding scheme,required bandwidth, and quality of service (QoS) for transmission ofvideo content. With a security gateway application, the applicationcontext information may describe a need for a security gateway,parameters for security processing, and an identity of the contentsource (e.g. content 103).

[0028] A packet data stream 305 may be generated by content source 103in order to support the application as established in transactionprocedure 301 and forwarded by current access router 109 to mobileterminal 101 a as packet data stream 305. Packets associated with packetdata stream 305 are typically delivered to mobile terminal 101 autilizing a care-of address (Internet Engineering Task Force RFC 3220and draft-ietf-mobileip-ipv6-16.txt) if mobile terminal 101 a is notlocated in a region that is served by its home agent such as a router.The care-of address is the termination point of a tunnel toward a mobilenode such as mobile terminal 101 a for packets forwarded to mobileterminal 101 a when mobile terminal 101 a is not located in its homeserving area.

[0029] If mobile terminal 101 a approaches the boundary between network120 and network 140, current access router 109 may determine that anIP-level handoff may occur. In the exemplary embodiment, a basetransceiver station that is serving mobile terminal 101 a and that isassociated with access router 109 measures the signal strength of mobileterminal 101 a (corresponding to the reverse/forward direction or theuplink/downlink). If the signal strength is below a signal threshold,the base transceiver station notifies current access router 109 aboutthe impending handoff When current access router 109 determines that anIP-level handoff may occur, current access router 109 provides newaccess router 113 with the application context information by sending anapplication context transfer message 307 to new access router 113. Theembodiment can utilize ICMP, UDP, TCP, stream control transmissionprotocol (SCTP) (Internet Engineering Task Force RFC 2960), or anymethod for transferring messages between two nodes in an IP network.Consequently, new access router 113 performs a discovery andconfiguration procedure 311 in order to find supplementary serviceprovider 117 or application-specific entity 217 that can provide theapplication-specific functionality in network 140 in order to supportthe media content being utilized by mobile terminal 101 b (as designatedfor the mobile terminal after a handoff 309). In the embodiment, newaccess router 113 can discover supplementary service provider 117 orapplication-specific entity 217 by using a static configuration (e.g.accessing a data structure that is maintained at new access router 113in which an address of supplementary service provider 117 orapplication-specific entity 217 is mapped to the required functionalityas deduced from the received application context), accessing a directoryagent that may be external to new access router 113, or sending amulticast query within network 140 that contains the profile of requiredapplication-specific functionality. New access router 113 may utilizeservice location protocol (Internet Engineering Task Force RFC 2165)with the inclusion of a proprietary or standardized field (serviceprofile) that designates the type of application-specific functionalitythat is required (e.g. transcoder or location-based service). With themulticast query, supplementary service provider 117 orapplication-specific entity 217 responds to the query if supplementaryservice provider 117 or application-specific entity 217 can supportmobile terminal 101 b in network 140.

[0030] New access router 113 also configures the application specificfunctionality with supplementary service provider 117 orapplication-specific entity 217. With a location-based supplementaryservice provider functionality, the application context information mayindicate that location service is required and may identify that contentsource 103 is authorized to receive location information about mobileterminal 103. New access router 113 may authorize supplementary serviceprovider 117 to provide information about mobile terminal 102 b tocontent source 103. New access router 113 can utilize protocols such asInternet control message protocol (ICMP), user datagram protocol (UDP),and transmission control protocol (TCP) to issue a command tosupplementary service provider 117.

[0031] With a message 313, new access router 113 provides informationabout supplementary service provider 117 or application-specific entity217 to content source 103. For a location tracking supplementary servicefunctionality, message 313 may include an address of supplementaryservice provider 117 and a new-care of address (associated with mobileterminal 101 b) to content source 103 so that content source 103 maymodify content that is dependent upon the location of mobile terminal101 b and deliver the content to mobile terminal 101 b. Delivery ofcontent commences with a packet data stream 315 when mobile terminal 101a handoffs to network 140 as a result of handoff trigger 309.

[0032]FIG. 4 shows a messaging scenario in which content source 103discovers and configures an application-specific functionality accordingto another exemplary embodiment of the invention. With a transactionsprocedure 401, mobile terminal 101 a and content source 103 set up adata session in order to initiate the packet data stream from currentcontent source 103 to mobile terminal 101 a. Typically, current accessrouter 109 is unaware of specific characteristics of end-userapplications being executed by mobile terminal 101 a. In the embodiment,hyper text transfer protocol is utilized, although other embodiments mayutilize session initiation protocol or other protocols. The content ofmessages, such as HTTP or SIP messages, that are exchanged betweenmobile terminal 101 a and content source 103 are typically not visibleto current access router 109 during transaction 401. Consequently, aregistration procedure 403 is executed by mobile terminal 101 a in orderto explicitly register application context information with currentaccess router 109. In the embodiment, registration procedure 403utilizes Internet control message protocol, user datagram protocol(UDP), transmission control protocol (TCP), or any standard method ofmessage transfer between nodes in an IP network. Other embodiments mayutilize other protocols such as hypertext transfer protocol.

[0033] A packet data stream 405 is generated by content source 103 inorder to support the application as established in transaction procedure401 and forwarded by current access router 109 to mobile terminal 101 aas packet data stream 405. Packets associated with packet data stream405 are typically delivered to mobile terminal 101 a utilizing a care-ofaddress if mobile terminal 101 a is not located in a region that isserved by its home agent (router). The care-of address is thetermination point of a tunnel toward mobile terminal 101 a for packetsforwarded to mobile terminal 101 a when mobile terminal 101 a is notlocated in its home serving area.

[0034] If mobile terminal 101 a approaches the boundary between network120 and network 140, current access router 109 may determine that anIP-level handoff may occur. In the embodiment, a base transceiverstation that is serving mobile terminal 101 a and that is associatedwith access router 109 measures the signal strength of mobile terminal101 a (corresponding to the forward/reverse direction or thedownlink/uplink). If the signal strength is below a signal threshold,the base transceiver station notifies current access router 109 aboutthe impending handoff. When current access router 109 determines that anIP-level handoff may occur, current access router 109 provides newaccess router 113 with the application context information by sending anapplication context transfer message 407 to new access router 113. Theembodiment can utilize ICMP, UDP, TCP, stream control transmissionprotocol (SCTP) (Internet Engineering Task Force RFC 2960), or anymethod for transferring messages between two nodes in an IP network. Newaccess router 113 processes the application context information. Theembodiment, for example, may determine the need for transcoding serviceif bandwidth capabilities of network 140 cannot support the completebandwidth requirements of the content. In such a case, new access router113 may compare bandwidth and QoS requirements that are specified in theapplication context information with the corresponding characteristicsof the IP connection between mobile terminal 101 b and new access router113. New access router may determine if application-specificfunctionality such as transcoding functionality is needed.

[0035] New access router 113 notifies content source 103 about the needfor application-specific functionality (e.g. transcoding functionality)as well as information such as a session identity, a new care-of-addressfor mobile terminal 101 b, and the characteristics of the IP connectionbetween mobile terminal 102 b and new access router 111 by sending amessage 411. Consequently, content source 103 initiates a discovery andconfiguration procedure 413.

[0036] Content source 103 performs discovery and configuration procedure413 in order to find supplementary service provider 117 orapplication-specific entity 217 that can provide theapplication-specific functionality to support the media content beingutilized by mobile terminal 101 b (as designated for the mobile terminalafter a handoff 409). In the exemplary embodiment, content source 103can discover supplementary service provider 117 or application-specificentity 217 by using a static configuration (e.g. accessing a datastructure that is maintained at content source 103 in which an addressof supplementary service provider 117 or application-specific entity 217is mapped to the required application-specific functionality), accessinga directory agent that may be external to content source 103, or sendinga multicast query that contains the profile of the requiredapplication-specific functionality. Content source 103 may utilize theservice location protocol with the inclusion of a proprietary orstandardized field (service profile) that designates the type ofapplication-specific that is required (e.g. transcoder or location-basedservice). With the multicast query, supplementary service provider 117or application-specific entity 217 responds to the query ifsupplementary service provider 117 or application-specific entity 217can support mobile terminal 101 b in network 140.

[0037] Content source 103 configures the application-specificfunctionality (e.g. transcoding functionality) by inviting supplementaryservice provider 117 or application-specific entity 217 to the session.In the exemplary embodiment, content source 103 sends a SIP INVITEmessage, in accordance with the session initiation protocol, tosupplementary service provider 117 or application-specific entity 217 inorder to provide information such as media and bandwidth information andthe new care-of address of mobile terminal 101 b. Content source 103consequently sends a SIP INVITE message to mobile terminal 102 b at thenew care-of address with appropriate information (e.g. information aboutthe transcoded packet stream) in order to complete the configurationprocedure. In the other embodiment, the content source 103 may send aconfirm message 415 to mobile terminal 102 b through new access router113 rather than send the SIP INVITE message to mobile terminal 102 b.

[0038] A packet data stream 417 (corresponding to the media transfer) isinitiated from content source 103 to mobile terminal 101 b. For anapplication-specific functionality such as transcoding, the mediatransfer is transmitted to application-specific entity 217 (acting as atranscoding proxy) and from application-specific entity 217 to mobileterminal 103 using the new care-of address of mobile terminal 101 b.

[0039]FIG. 5 shows a messaging scenario in which a hybrid approach isutilized to discover and to configure an application-specificfunctionality according to another exemplary embodiment of theinvention. With a transactions procedure 501, mobile terminal 0la andcontent source 103 set up a data session in order to initiate a packetdata stream from current content source 103 to mobile terminal 101 a.Typically, current access router 109 is unaware of specificcharacteristics of end-user applications being executed by mobileterminal 101 a. In the embodiment, hyper text transfer protocol isutilized, although other embodiments may utilize session initiationprotocol or other protocols. The content of the HTTP or SIP messagesthat are exchanged between mobile terminal 101 a and content source 103are typically not visible to current access router 109 duringtransaction 501. Consequently, a registration procedure 503 is executedby mobile terminal 101 a in order to explicitly register applicationcontext information with current access router 109. In the embodiment,registration procedure 503 utilizes Internet control message protocol,user datagram protocol (UDP), transmission control protocol (TCP), orany standard method of message transfer between nodes in an IP networkOther embodiments may utilize other protocols such as hypertext transferprotocol.

[0040] A packet data stream 505 is generated by content source 103 inorder to support the application as established in transaction procedure501 and forwarded by current access router 109 to mobile terminal 101 aas packet data stream 505. Packets associated with packet data stream505 are typically delivered to mobile terminal 101 a utilizing a care-ofaddress if mobile terminal 101 a is not located in a region that isserved by its home agent (router). The care-of address is thetermination point of a tunnel toward mobile terminal 101 a for packetsforwarded to mobile terminal 101 a when mobile terminal 101 a is notlocated in its home serving area.

[0041] If mobile terminal 101 a approaches the boundary between network120 and network 140, current access router 109 may determine that anIP-level handoff may occur. In the embodiment, a base transceiverstation that is serving mobile terminal 101 a and that is associatedwith access router 109 measures the signal strength of mobile terminal101 a (corresponding to the forward/reverse direction or thedownlink/uplink). If the signal strength is below a signal threshold,the base transceiver station notifies current access router 109 aboutthe impending handoff. When current access router 109 determines that anIP-level handoff may occur, current access router 109 provides newaccess router 113 with the application context information by sending anapplication context transfer message 507 to new access router 113. Theembodiment can utilize ICMP, UDP, TCP, stream control transmissionprotocol (SCTP) (Internet Engineering Task Force RFC 2960), or anymethod for transferring messages between two nodes in an IP network. Newaccess router 113 processes the application context information.

[0042] Consequently, new access router 113 performs a discoveryprocedure 509 in order to find supplementary service provider 117 orapplication-specific entity 217 that can provide theapplication-specific functionality to support the media content beingutilized by mobile terminal 101 b (as designated for the mobile terminalafter a handoff 511). In the embodiment, new access router 113 candiscover supplementary service provider 117 or application-specificentity 217 by using a static configuration (e.g. accessing a datastructure that is maintained at new access router 113 in which anaddress of supplementary service provider 117 or application-specificentity 217 is mapped to the profile of the required application-specificfunctionality), accessing a directory agent that may be external to newaccess router 113, or sending a multicast query that contains theprofile of the required application-specific functionality. New accessrouter 113 may utilize the service location protocol with the inclusionof a proprietary or standardized field (service profile) that designatesthe type of application-specific that is required (e.g. transcoder orlocation-based service). With the multicast query, supplementary serviceprovider 117 or application-specific entity 217 responds to the query ifsupplementary service provider 117 or application-specific entity 217can support mobile terminal 101 b in network 140.

[0043] With a variation of the embodiment, current access router 109 mayperform discovery procedure 509 in order to find supplementary serviceprovider 117 or application-specific entity 217 that can provide theapplication-specific functionality in network 140. In such a case,current access router 109 provides information aboutapplication-specific functionality to content source 103.

[0044] Subsequent to new access router 113 discovering supplementaryservice provider 117 or application-specific entity 217 that can supportthe application-specific functionality, new access router sends amessage 513 to content source 103 with information about theapplication-specific functionality that was discovered during procedure509. New access router 113 also sends a message 521 to mobile terminal101 b with information about the application-specific functionality thatmay include the address of application-specific entity 217 orsupplementary service provider 117. Mobile terminal 101 b may authorizeapplication-specific entity 217 or supplementary service provider 117 toprovide the application-specific functionality for its applications.Also, mobile terminal 101 b may also create any states that are neededfor availing the functionality. Mobile terminal 101 b completes theconfiguration with network 140 with an establishment procedure 523 andconfirms the configuration by sending a confirm message 525 to newaccess router 113. Content source 103 completes the configuration withsupplementary service provider 117 or application-specific entity 217with a procedure 515. For example, for an application-specificfunctionality corresponding to a security gateway, content source 103may build a security association with the security gateway (e.g.application-specific entity 217).

[0045]FIG. 6 shows apparatus for mobile terminal 105, an access router610 (e.g. current access router 109 and new access router 113), acontent source 620 (e.g. content source 103) in accordance with theexemplary embodiments of the invention. Mobile terminal 105 comprises aprocessor 601, a communications interface 603, and a memory 605. Mobileterminal 105 communicates over wireless channel 108 throughcommunications interface 603. Processor 601 executes a software programfrom memory 605 in accordance with the message scenarios shown in FIGS.3, 4, and 5.

[0046] Access router 610 comprises a processor 611, ports 613 and 615,and a memory 617. Processor 611 communicates with a base transceiverstation through port 613 through an IP path 650 and with content source620 through port 615 and an IP path 651. Processor 611 executes asoftware program from memory 617 in accordance with the messagescenarios shown in FIGS. 3, 4, and 5.

[0047] Content source 620 comprises a processor 621, a port 623, aprogram memory 625 and a media memory 627. Processor 621 communicateswith access router 610 through port 623 and IP path 651. Processor 621executes a software program from program memory 625 in accordance withthe message scenarios shown in FIGS. 3, 4, and 5. Also, processor 621generates a packet data stream by accessing media memory 627 in order toobtain the media content that is being played for the data session.

[0048] As can be appreciated by one skilled in the art, a computersystem with an associated computer-readable medium containinginstructions for controlling the computer system can be utilized toimplement the exemplary embodiments that are disclosed herein. Thecomputer system may include at least one computer such as amicroprocessor, digital signal processor, and associated peripheralelectronic circuitry.

[0049] While the invention has been described with respect to specificexamples including presently preferred modes of carrying out theinvention, those skilled in the art will appreciate that there arenumerous variations and permutations of the above described systems andtechniques that fall within the spirit and scope of the invention as setforth in the appended claims.

I/We claim:
 1. A mobile terminal for supporting a relocation of anapplication-specific functionality during a network layer-level handoff,comprising: a communications interface; a processor communicatingthrough the communications interface, the processor configured to causethe mobile terminal to perform the steps of: (a) initiating anapplication with a content source; (b) receiving a packet data streamthat is associated with the application; (c) registering applicationcontext information comprising an application-specific functionalityinformation; and (d) continuing to receive the packet data stream inresponse to the mobile terminal completing the network layer-levelhandoff
 2. The mobile terminal of claim 1, wherein the processor isconfigured to perform the further step of: (e) initiating the networklayer-level handoff.
 3. The mobile terminal of claim 1, wherein theprocessor is configured to perform the further step of: (e) receiving asecond information comprising an address of an entity that provides theapplication-specific functionality.
 4. The mobile terminal of claim 3,wherein the processor is configured to perform the further comprisingthe step of: (f) adjusting a processing of the packet data stream inaccordance with the second information.
 5. The mobile terminal of claim3, wherein the second information is selected from the group consistingof a bandwidth requirement and a media format.
 6. The mobile terminal ofclaim 3, wherein the processor is configured to perform the further stepof: (f) communicating with the entity in order to establish a state thatis required to avail the application-specific functionality.
 7. Themobile terminal of claim 3, wherein the processor is configured toperform the further step of: (f) authorizing the entity to perform theapplication-specific functionality.
 8. An access router for supporting arelocation of an application-specific functionality during a networklayer-level handoff, comprising: a data port; a processor communicatingthrough the data port, the processor configured to cause the accessrouter to perform the steps of: (a) receiving a registration messagecontaining application context information, the application contextinformation comprising an application-specific functionalityinformation; and (b) sending the application context information toanother access router.
 9. An access router for supporting a relocationof an application-specific functionality during a network layer-levelhandoff, comprising: a data port; a processor communicating through thedata port, the processor configured to cause the access router toperform the steps of (a) receiving a registration message containingapplication context information, the application context informationcomprising an application-specific functionality information; (b)discovering an entity that shall provide the application-specificfunctionality; and (c) providing an address and additional informationabout the entity to a communication end-point.
 10. The access router ofclaim 9, wherein the communication end-point is selected from the groupconsisting of a mobile terminal and a content source.
 11. An accessrouter for supporting a relocation of an application-specificfunctionality during a network layer-level handoff, comprising: a dataport; a processor communicating through the data port, the processorconfigured to cause the access router to perform the steps of (a)receiving an application context information, the application contextinformation comprising an application-specific functionalityinformation; (b) discovering an entity that shall perform theapplication-specific functionality; (c) configuring theapplication-specific functionality for a mobile terminal with the entityin response to the network-layer handoff; and (d) providing an addressand additional information about the entity to a communicationend-point.
 12. The access router of claim 11, wherein the processor isconfigured to perform the further step of (e) comparing contents of theapplication context information with characteristics of a connectionbetween the access router and the mobile terminal in order to determinethe application-specific functionality.
 13. The access router of claim11, wherein step (b) comprises the steps of: (i) sending a multicastquery within an associated network, the query containing an indicatorabout the application-specific functionality; and (ii) receiving aresponse from the entity, the response indicating that the entity cansupport the application-specific functionality.
 14. The access router ofclaim 11, wherein step (b) comprises the step of (i) accessing a datastructure that contains configuration information about theapplication-specific functionality.
 15. The access router of claim 11,wherein step (b) comprises the steps of (i) querying a directory agentabout the application-specific functionality; and (ii) receiving aresponse from the directory agent about the entity.
 16. The accessrouter of claim 11, wherein step (b) utilizes a service profile, theservice profile designating a type of application-specific functionality17. The access router of claim 11, wherein step (c) comprises the stepof (i) establishing the application-specific functionality for themobile terminal with the entity.
 18. The access router of claim 11,wherein step (c) comprises the step of: (i) authorizing theapplication-specific functionality for the mobile terminal with theentity.
 19. The access router of claim 11, wherein theapplication-specific functionality comprises a supplementary servicefunctionality.
 20. The access router of claim 11, wherein thecommunication end-point is selected from the group consisting of themobile terminal and a content source.
 21. A content source forsupporting a relocation of an application-specific functionality duringa network layer-level handoff comprising: a port; a memory; and aprocessor that accesses the memory to obtain media content, forms apacket data stream from the media content, and sends the packet datastream through the port in order to support an application, theprocessor configured to cause the content source to perform the steps of(a) responding to an initiation of the application with a mobileterminal; (b) sending the packet data stream that is associated with theapplication; (c) receiving information comprising an address of anentity that provides the application-specific functionality; and (d)continuing to send the packet data stream in response to the mobileterminal completing the network layer-level handoff.
 22. An accessrouter for supporting a relocation of an application-specificfuictionality during a network layer-level handoff of a mobile terminal,comprising: a data port; a processor communicating through the dataport, the processor configured to cause the access router to perform thesteps of (a) receiving an application context information, theapplication context information comprising an application-specificfunctionality information; and (b) providing session information aboutthe application-specific functionality.
 23. The access router of claim22, wherein the processor is configured to perform the further step of:(c) comparing contents of the application context information withcharacteristics of a connection between the access router and the mobileterminal in order to determine the application-specific functionality.24. The access router of claim 22, wherein the session informationcomprises a description of the application-specific functionality and anew care-of address that is associated with the mobile terminal.
 25. Theaccess router of claim 22, wherein the session information comprises anaddress of an entity, the entity being capable of discovering theapplication-specific functionality.
 26. A content source for supportinga relocation of an application-specific functionality during a networklayer-level handoff comprising: a port; a memory; and a processor thataccesses the memory to obtain media content, forms a packet data streamfrom the media content, and sends the packet data stream through theport in order to support an application, the processor configured tocause the content source to perform the steps of: (a) responding to aninitiation of the application with a mobile terminal; (b) sending thepacket data stream that is associated with the application; (c)receiving information about the application-specific functionality; (d)discovering an entity that shall perform the application-specificfunctionality; (e) configuring the application-specific functionalityfor a mobile terminal with the entity in response to the network-layerhandoff; and (f) continuing to send the packet data stream in responseto the mobile terminal completing the network layer-level handoff
 27. Anaccess router for supporting a relocation of an application-specificfunctionality during a network layer-level handoff of a mobile terminal,comprising: a data port; a processor communicating through the dataport, the processor configured to cause the access router to perform thesteps of (a) receiving an application context information, theapplication context information comprising an application-specificfunctionality information; (b) discovering an entity that shall performthe application-specific functionality; and (c) providing informationabout the application-specific functionality and an address to acommunication end-point.
 28. A content source for supporting arelocation of an application-specific functionality during a networklayer-level handoff comprising: a port; a memory; and a processor thataccesses the memory to obtain media content, forms a packet data streamfrom the media content, and sends the packet data stream through theport in order to support an application, the processor configured tocause the content source to perform the steps of (a) responding to aninitiation of the application with a mobile terminal; (b) sending thepacket data stream that is associated with the application; (c)receiving information about the application-specific functionalitycomprising an address of an entity that can provide theapplication-specific functionality; (d) configuring theapplication-specific functionality for a mobile terminal with an entitycorresponding to the information; and (e) continuing to send the packetdata stream in response to the mobile terminal completing the networklayer-level handoff.
 29. A method for supporting a relocation of anapplication-specific functionality with a mobile terminal during anetwork layer-level handoff in a wireless system, the method comprisingthe steps of (a) initiating an application with a content source; (b)receiving a packet data stream that is associated with the application;(c) registering an application context information comprising anapplication-specific functionality information; (d) continuing toreceive the packet data stream in response to the mobile terminalcompleting the network layer-level handoff.
 30. The method of claim 29,further comprising the step of (e) initiating the network layer-levelhandoff
 31. The method of claim 29, further comprising the step of (e)receiving a second information comprising an address of an entity thatprovides the application-specific functionality.
 32. The method of claim31, further comprising the step of: (f) adjusting a processing of thepacket data stream in accordance with the second information.
 33. Amethod for supporting a relocation of an application-specificfunctionality provided for an application on a mobile terminal during anetwork layer-level handoff in a wireless system, the wireless systemcomprising an access router, the method comprising the steps of (a)receiving a registration message containing application contextinformation, the application context information comprising anapplication-specific functionality information; and (b) sending theapplication content information to another entity.
 34. The method ofclaim 33, wherein the other entity is another access router.
 35. Amethod for supporting a relocation of an application-specificfunctionality provided for an application on a mobile terminal during anetwork layer-level handoff in a wireless system, the wireless systemcomprising an access router, the method comprising the steps of: (a)receiving a registration message containing application contentinformation, the application content information comprising anapplication-specific functionality information; (b) discovering anentity that shall perform the application-specific functionality; and(c) providing an address and additional information about the entity toa communication end-point.
 36. A method for supporting a relocation ofan application-specific functionality provided for an application on amobile terminal during a network layer-level handoff in a wirelesssystem, the wireless system comprising an access router, the methodcomprising the steps of: (a) receiving an application contextinformation, the application context information comprising anapplication-specific functionality information; (b) discovering anentity that shall perform the application-specific functionality; (c)configuring the application-specific functionality for the mobileterminal with the entity in response to the network-layer handoff; and(d) providing an address and additional information about the entity toa communication end-point.
 37. The method of claim 36, the methodcomprising the further step of: (e) comparing contents of theapplication context information with characteristics of a connectionbetween the access router and the mobile terminal in order to determinethe application-specific functionality.
 38. The method of claim 36,wherein step (b) comprises the steps of: (i) sending a multicast querywithin an associated network, the query containing an indicator aboutthe application-specific functionality; and (ii) receiving a responsefrom the entity, the response indicating that the entity can support theapplication-specific functionality.
 39. The method of claim 36, whereinstep (c) comprises the step of: (i) establishing theapplication-specific functionality for the mobile terminal with theentity.
 40. The method of claim 36, wherein step (c) comprises the stepof: (i) authorizing the application-specific functionality for themobile terminal with the entity.
 41. A method for supporting arelocation of an application-specific functionality provided for anapplication on a mobile terminal during a network layer-level handoff ina wireless system, the wireless system comprising a content source, themethod comprising the steps of: (a) responding to an initiation of theapplication with the mobile terminal; (b) sending a packet data streamthat is associated with the application; (c) receiving informationcomprising an address of an entity that supports theapplication-specific functionality; and (d) continuing to send thepacket data stream in response to the mobile terminal completing thenetwork layer-level handoff.
 42. A method for supporting a relocation ofan application-specific functionality provided for an application on amobile terminal during a network layer-level handoff in a wirelesssystem, the wireless system comprising an access router, the methodcomprising the steps of: (a) receiving an application contextinformation, the application context information comprising anapplication-specific functionality information; and (b) providingsession information about application-specific functionality.
 43. Themethod of claim 42, further comprising the step of: (c) comparingcontents of the application context information with characteristics ofa connection between the access router and the mobile terminal in orderto determine the application-specific functionality.
 44. A method forsupporting a relocation of an application-specific functionalityprovided for an application on a mobile terminal during a networklayer-level handoff in a wireless system, the wireless system comprisinga content source, the method comprising the steps of: (a) responding toan initiation of the application with the mobile terminal; (b) sendingthe packet data stream that is associated with the application; (c)receiving information about the application-specific functionality; (d)discovering an entity that shall perform the application-specificfunctionality; (e) configuring the application-specific functionalityfor the mobile terminal with the entity in response to the network-layerhandoff; and (f) continuing to send the packet data stream in responseto the mobile terminal completing the network layer-level handoff.
 45. Amethod for supporting a relocation of an application-specificfunctionality provided for an application on a mobile terminal during anetwork layer-level handoff in a wireless system, the wireless systemcomprising an access router, the method comprising the steps of: (a)receiving an application context information, the application contextinformation comprising an application-specific functionalityinformation; (b) discovering an entity that shall perform theapplication-specific functionality; and (c) providing sessioninformation about application-specific functionality.
 46. A method forsupporting a relocation of an application-specific functionality with amobile terminal during a network layer-level handoff in a wirelesssystem, the wireless system comprising a content source, the methodcomprising the steps of: (a) responding to an initiation of anapplication with the mobile terminal; (b) sending the packet data streamthat is associated with the application; (c) receiving information aboutthe application-specific functionality; (d) configuring theapplication-specific functionality for the mobile terminal with anentity corresponding to the information; and (f) continuing to send thepacket data stream in response to the mobile terminal completing thenetwork layer-level handoff.
 47. A computer-readable medium containinginstructions for supporting a relocation of an application-specificfunctionality during a network layer-level handoff in a wireless system,comprising instructions that cause a mobile terminal to perform thesteps of: (a) initiating an application with a content source; (b)receiving a packet data stream that is associated with the application;(c) registering an application context information comprising anapplication-specific functionality information; and (d) continuing toreceive the packet data stream in response to the mobile terminalcompleting the network layer-level handoff.
 48. A computer-readablemedium containing instructions for supporting a relocation of anapplication-specific functionality during a network layer-level handoffin a wireless system, the wireless system comprising an access router,comprising instructions that cause the access router to perform thesteps of: (a) receiving a registration message containing applicationcontext information, the application content information comprising anapplication-specific functionality information; and (b) sending theapplication content information.
 49. A computer-readable mediumcontaining instructions for supporting a relocation of anapplication-specific functionality during a network layer-level handoffin a wireless system, the wireless system comprising an access router,comprising instructions that cause the access router to perform thesteps of: (a) receiving an application context information, theapplication context information comprising an application-specificfunctionality information; and (b) providing information aboutapplication-specific functionality.
 50. The computer-readable medium ofclaim 49, further comprising instructions that cause the access routerto perform the step of: (c) discovering an entity that shall perform theapplication-specific functionality.
 51. The computer-readable medium ofclaim 50, further comprising instructions that cause the access routerto perform the step of (d) configuring the application-specificfunctionality for a mobile terminal with the entity in response to thenetwork-layer handoff
 52. A mobile terminal for supporting a relocationof an application-specific functionality during a network layer-levelhandoff, comprising: a communications interface; a processorcommunicating through the communications interface, the processorconfigured to cause the mobile terminal to perform the steps of: (a)initiating an application with a content source; (b) receiving a packetdata stream that is associated with the application; (c) registering anapplication context information comprising an application-specificfunctionality information; (d) receiving a second information comprisingan address of an entity that provides the application-specificfunctionality; (e) continuing to receive the packet data stream; and (f)processing the packet data stream in accordance with the secondinformation.